Thread braking device

ABSTRACT

In the case of a thread braking device (B), which is intended to be used especially on the supply side of a thread feeder (F) and which comprises a thread brake (3) having a fixed passage axis (f) and having arranged thereon a shield surface (A) provided with a thread opening (22) and arranged transversely to the direction (R) in which the thread (Y) is supplied, there are provided direction adjustment means (M) for the shield surface (A), with the aid of which the transverse position of said shield surface (A) can be adjusted to supply directions (R1, R2) of the thread (Y) deviating from the passage axis (f). Even in the case of a shield surface (A) for general thread-guiding tasks, which is arranged in a stationary holding means and oriented transversely to the supply direction (R) of the thread (Y), such position adjustment means are provided so that the transverse position of the shield surface (A) can be adjusted to the respective supply direction (R1, R2) of the thread (Y).

DESCRIPTION

The present invention refers to a thread braking device.

When a thread is supplied from a supply coil to a consumer, e.g. aweaving machine or a knitting machine, a thread feeder will be used foreliminating variations of thread tension and for offering the thread tothe consumer under the best possible conditions. Thanks to the threadfeeders, an extraordinary increase in the processing speed could beachieved without increasing the strength of the thread. The threadfeeder, e.g. a thread storage and feed device, has its axis positionedin alignment with the location where the thread is inserted into theconsumer, e.g. the shed of a weaving machine, so as to guarantee thesmallest possible deflection in the thread path to the consumer. One orseveral thread supply coil(s) from which the thread feeder draws off thethread can, normally, not be brought into alignment with the then fixedaxis of the thread feeder. The reason for this is to be seen in spaceconditions and in the way in which the operators change the supplycoils. The knotting together of threads coming from several supply coilswill automatically result in various directions of supply to the threadfeeder. For guaranteeing proper functioning of the thread feeder, acertain basic tension of the thread coming from the supply coil will beexpedient. Hence, a thread braking device is provided on the supply sideof the thread feeder. In order to prevent the incoming thread fromgetting entangled in the thread braking device, a shield surface isfixedly arranged on the thread braking device, said shield surface beingeither a flat plate or a spherical cup. The shield surface should bepositioned transversely to the supply direction of the thread so thatthe surface producing the shielding effect is as large as possible. Itis therefore necessary to position the thread braking device such thatit extends at an oblique angle relative to the axis of the threadfeeder. This, however, will result in an undesired deflection of thethread between the thread braking device and the thread feeder, i.e. ata location in the thread path ahead of which the braking device producestension in the thread. Depending on the deflection angle and thefriction, this will cause an augmentation in tension increases and,especially, tension peaks which are generated when the thread is unwoundfrom the supply coil. This will result in the risk of thread breakage.

Sometimes, at least one thread opening has to be arranged in astationary manner along the path from the supply coil to the consumer.In order to prevent the thread, which is animated (ballooning) duringits journey and which will occasionally sag in response to speedvariations, from getting entangled in the obstacle formed by said threadopening, the thread opening will be arranged in a large-area shieldsurface, which is positioned transversely to the supply direction of thethread and which will prevent the thread from getting entangled, wherebythread breakage would be caused.

The present invention is based on the task of providing a thread brakingdevice and a shield surface, respectively, by means of which theabove-mentioned disadvantages are avoided. In the case of a threadbraking device located on the supply side of a thread feeder, the numberof thread breakages is to be reduced. In the case of a shield surfaceused for general thread guiding tasks, the best possible shieldingeffect, which will prevent thread breakage in this area, is to be alwaysguaranteed.

The thread braking device, which is intended to be used on the supplyside of the thread feeder, can be aligned with the axis of said threadfeeder in such a way that there will be no deflection downstream of thethread brake, which would increase the risk of thread breakage. Also therisk of entangling of the thread in the thread braking device is reducedbecause the shield surface can be adjusted to the supply direction ofthe thread in each case in such a way that the shield surface whichbecomes effective is as large as possible.

In the case of a shield surface which is provided with a thread openingand which is used for general thread guiding tasks, said shield surfacewill produce the optimum shielding effect due to its adjustment to thesupply direction. In both cases, it is of essential importance that theshield surface can be adjusted, at least approximately, transversely tothe supply direction, and this will be possible with the aid of thedirection adjustment means.

In both cases, there is no necessity of providing--as has often beennecessary up to now--an oversized shield surface, since said shieldsurface can individually be adjusted to the thread supply direction.Under the normally narrow space conditions in the case of threadprocessing, this is of essential importance, since several threads areoften supplied to a consumer and since it will then be necessary tocoordinate a corresponding number of thread feeders, shield surfaces andthread braking devices as well as an even larger number of supply coilssuch that they occupy the least possible space.

The direction adjustment means which are constructed as positiveengagement arrangement guarantee a precise adjustment of the shieldsurface as well as exactly reproducable positions of adjustment, whereasthe frictional engagement means used for securing the shield surface inposition during operation will take up unavoidable reaction forcesresulting from vibrations.

An additional advantageous embodiment, in the case of which a basicmember is provided, which is adapted to be supported in a stationarymanner and which is equipped with a holding member for the shieldsurface. The holding member fulfills the additional task of contributingto the adjustment of the shield surface.

Another structurally expedient embodiment is the embodiment wherein theshield surface is provided with part of the direction adjustment means.

In another embodiment, the support means of the basic member isadditionally used for effecting the respective correct adjustment of theshield surface.

A particularly expedient embodiment, which is reliable in function andeasy to handle, the shield surface is reliably held in the rotaryconnection. Adaptation of the shield surface to the respective supplydirection is achieved simply by the rotary motion of the shield surfacerelative to the basic member and of the basic member relative to theshield surface, said rotary motion being carried out for the purpose ofadjustment.

Another embodiment covers, between 0° and 45°, all deviations betweenthe thread passage axis in the thread brake and the supply direction ofthe thread. If the supply direction should deviate more than 45° fromthe passage axis, the 45°-inclined position of the shield surface willstill produce a sufficient shielding effect. For larger angulardeviations, the inclined position angles can also be larger and/ordifferent from one another.

In an additional expedient embodiment, a ball-and-socket joint or auniversal joint permits a simple adaptation of the transverse positionof the shield surface to arbitrary supply directions of the thread.

Alternatively, the respective adjustment position of the shield surfaceis established by superimposing a pivotal movement of the shield surfaceabout the axis of rotation and a rotary motion of the basic member aboutthe passage axis.

In another embodiment, the basic member is adapted to be rotatedrelative to the support means.

It is, however, also imaginable to reposition the basic member with itssupport means about the passage axis so as to adjust the shield surfaceto the supply direction of the thread.

In the case of another embodiment a spherical cup will produce aparticularly good shielding effect against entanglement.

In a structurally simple and reliable embodiment, the oblique positionof the holding means relative to the passage axis and the obliqueposition of the end face of the extension relative to the shield surfaceitself determine the maximum possible oblique position of the shieldsurface, which can be adjusted by rotation. The shield surface is fixedby means of the counternut in the respective position which has beenadjusted. The individual components can easily be produced. Therespective repositioning operations can be carried out rapidly and withthe aid of simple tools. Vibrations will not change the position ofadjustment which has been chosen for the shield surface.

With respect to the best possible careful treatment of the thread, theincoming thread is essentially deflected at the thread eye positioned onthe supply side. The additional thread eye positioned behind saidfirst-mentioned thread eye will be touched by the thread only in thecase of extreme transverse movements.

BRIEF DESCRIPTION OF THE DRAWINGS

Embodiments of the subject matter of the invention will be explained onthe basis of the drawings, in which:

FIG. 1 shows a side view of a thread braking device,

FIG. 2 shows part of the thread braking device of FIG. 1 after anadjustment which has been carried out, FIG. 1 and 2 each representinglimit adjustments,

FIG. 3 shows a section in plane III--III of FIG. 2,

FIG. 4 shows a sectional side view of a shield surface which issupported in a stationary manner and which belongs e.g. to a threadbraking device,

FIG. 5 shows a side view of an additional embodiment of a thread brakingdevice,

FIG. 6 shows a scheme for elucidating geometrical conditions when athread is being processed, and

FIG. 7 shows an exploded sectional side view of the thread brakingdevice of FIG. 1.

DETAILED DESCRIPTION

FIG. 1 and 2 disclose a thread braking device B of the type provided onthe supply side of a thread feeder F when a thread is being processed(FIG. 6). A shield surface A according to FIG. 4 can be integrated inthe thread braking device B as disclosed in FIG. 1, 2, 3, 4 and 5. Itis, however, also imaginable to arrange the shield surface A accordingto FIG. 4 without any braking device at a different point in the path ofthe thread Y in FIG. 6 so as to fulfil general thread guiding functions,e.g. between the thread feeder F and a consumer C.

In FIG. 6, the consumer C is a weaving machine processing the thread Yas a weft thread. The thread Y is stored on thread supply coils Sprovided in a holding means H. The threads of thread supply coils Sbelonging together are knotted together so that a change from an emptysupply coil S to a full one will take place automatically. The threadfeeder F is a thread storage and feed device by means of which thethread Y is drawn off the supply coil S, stored intermediately andoffered at a uniformly low thread tension to the consumer C, which willdraw off the thread Y according to requirements. The axis of the threadfeeder F is approximately in alignment with the point of insertion atthe consumer C, e.g. in the case of single-color weaving carried outwith one thread feeder.

For reasons of space (in the case of several alternately working threadfeeders F, F'), it may be necessary to arrange each thread feeder F suchthat its axis extends at an oblique angle.

A shield surface A having an incoming thread guide opening 22a for thethread, can also be arranged between the thread feeder and the consumeror at a different point of the thread path (FIG. 6), e.g. in the area ofan intermediate nozzle or a threading nozzle, which is used forautomatic threading and at which the thread is to be prevented fromgetting entangled in spite of ballooning.

The thread braking device B, which has a thread passage axis f, isinstalled on the supply side of the thread feeder F.

The supply direction of the thread from the supply coil S deviates fromthe passage axis f (cf. FIG. 6), said supply direction being referred toby reference symbol R. The thread braking device B has attached theretoa shield surface A, which has to extend at right angles to the supplydirection R so as to prevent entanglement in the case of sagging orballooning. Direction adjustment means M for the shield surface A areprovided on the thread braking device B, said direction adjustment meansM being used for adapting the transverse position of the shield surfaceA to the respective supply direction R. The shield surface A can,fundamentally, be adjusted to a mean or average supply direction.

The thread braking device B according to FIG. 1, 2 and 7 includes abow-shaped basic member or support frame 1 provided with a holdingmember 2, which has secured thereto a thread brake 3. In the case of theembodiment shown, the braking device is a disk brake with disks 3a, 3b,which are pressed together by a spring 3c and which are movablysupported on a support 3f fixed in position by means of a nut 3e. Theclamping force of the spring 3c can be varied by means of an adjustmentscrew 3d.

At the lower end of the holding member 2, a support means or means forrotatably positioning the frame 4 in the form of a quadrangular plate isarranged, which includes fastening means 5, e.g. elongated holes, withthe aid of which the thread braking device B is fixed at the supply sideof the thread feeder F. The elongated holes 5 are distributedconcentrically around a central thread eye 6 so that the basic member 1can respectively be repositioned by 90° in the direction of an arrow 21,or can be advanced by one throughhole, and so that said basic member 1can also be rotated to a limited extent.

At the upper end, the holding member 2 is provided with a tongue 7having an upper surface 8 and a lower surface 9. The thread brakingdevice B has a stationary or fixed incoming thread passage axis f, whichis in alignment with the axis of the thread feeder F in FIG. 6 so as toexclude any deflection of the thread Y between the thread brake 3 andthe thread feeder.

The direction adjustment means M will be explained hereinbelow. Theshield surface A, which is constructed as a shield member or sphericalcup 11 consisting of plastic material or of sheet metal, has at its backan extension or central base portion 12 having an end face 15 whichextends at an oblique angle B relative to the plane 16 of the shieldsurface A and which rests on the surface 8 of the tongue 7. The tongue 7extends at an oblique angle φ relative to the passage axis f. Theextension 12 is provided with a hollow threaded projection 17, whichprojects through an opening 7a of the tongue 7. The projection 17includes an outgoing thread guide opening 22b located close to butdownstream of the incoming thread guide opening 22a. The outgoing threadguide opening 22b permits the incoming thread Y, when discharged fromthe direction adjustment means, to be supplied to the thread brake Balong the fixed thread passage axis f. The outgoing thread guide openingintersects the fixed thread passage axis f when the shield member isadjustably moved between at least first and second adjustment positionswhich correspond to first and second incoming thread supply directionsR₁ and R₂, respectively. A positive locking means or counternut 18 isscrewed onto the threaded projection 17, said counternut 18 abutting onthe surface 9 of the tongue 7. The threaded projection 17 has arrangedtherein a thread eye 19, which consists of ceramics and the center ofwhich is positioned in the passage axis f. A thread eye 13 consisting ofceramics is also arranged within the incoming thread guide opening 22aon the supply side of the shield surface A. A thread guide passage 22extends between the two thread eyes 13 and 19 within the spherical cup11. The guide passage 22 has a first portion which extends centrallywithin the extension 12 along a longitudinal central axis orientedperpendicularly to the plane 16, and a second portion which extendscentrally within the projection 17 along an axis of rotation 10, whichaxis 10 extends at an angle to the longitudinal central axis.

Referring now to FIG. 7, there is shown an exploded view of thedirection adjustment means M. The direction adjustment means M comprisestwo parts. The first part includes the extension 12 and the projection17, and the second part includes the tongue 7 having the bore 7atherethrough. The first and second parts cooperate to define a rotaryconnection D. The threaded projection 17 extends perpendicularlydownstream from the end face surface 15 and is oriented along the axisof rotation 10. The thread guide passage 22 terminates at an upstreamside with the incoming thread guide opening 22a, and terminates at thedownstream side with the outgoing thread guide opening 22b. The incomingand outgoing thread guide openings 22a and 22b have the thread eyes 13and 19 respectively secured therein. Thread eye 13 includes an annularflange 13a which abuts shield surface A, and thread eye 19 includes anannular flange 19a which abuts a free edge of projection 17. Counternut18 slidably passes over annular flange 19a to threadedly engage theprojection 17. The annular flange 19a does not extend radially beyondthe external threads of the projection 17.

The extension 12 is secured in position on the tongue 7 by means of therotary connection D. The rotary connection D has the axis of rotation10, which extends at an oblique angle, perpendicularly to the tongue 7,and which crosses the passage axis f. The axis of rotation 10 extends atan oblique angle α relative to the passage axis f. The angle β isprovided between the plane 16 of the shield surface A and a plane 14extending at right angles relative to said axis of rotation 10. In thecase of the embodiment shown, the angles α and β are each approx. 22.5°.The angles α and β can be different from each other, and their sum canexceed 45°.

When the shield surface is to be adjusted, counternut 18 is firstloosened, then the spherical cup 11 is rotated about the axis ofrotation 10 to obtain the desired shield surface position, and then thecounternut 18 is tightened to secure the position of the spherical cup11 on the tongue 7.

In the first adjustment position of the shield surface A according toFIG. 2, the supply direction R1 of the thread Y deviates from thepassage axis f by 45° The extension 12 of the shield surface A has beenrotated to a maximum limit position relative to the tongue 7. The anglesα and β sum to approximately 45°. The plane 16 of the shield surface Aextends approximately at right angles to the supply direction R1. Byrotating the shield surface A (after having loosened the counternut 18),said shield surface A can be adjusted to any thread supply directionbetween 0° and 45°.

In FIG. 1, it is indicated that, in the second limit position of theshield surface A, the two angles α and β nullify each other, and thatstraight passage in the direction of the passage axis f is given for athread supply direction R which is in alignment with said passage axisf. The angle α, is defined between the axis of rotation 10 and thepassage axis f, whereras the angle β is to be measured between the planeof the shield surface A and a plane 14, which extends at right angles tothe axis of rotation 10.

If the supply direction R1 lies in the plane of the drawing such thatthe thread is supplied from the left side to the thread braking deviceB, the basic member 1 will be repositioned by 180° about the passageaxis f. If the supply direction R1 extends into the plane of the drawingfrom the front or from the rear, the basic member 1 will be repositionedaccordingly and rotated in the elongated holes 5 such that the plane 16of the shield surface extends approximately at right angles to saidsupply direction.

The shield surface A according to FIG. 4 is a spherical cup consistingof plastic material or of sheet metal. At the back of said spherical cup11, an extension 12' is formed, which has approximately the shape of aball and through which the thread opening 22 extends; the thread eye 13and, possibly, but not necessarily, the additional thread eye 19 arepositioned in said thread opening 22. The ball-shaped surface of theextension 12' is enclosed by a spherical holding ring 23, which can beslotted, if desired, and which is provided with tensioning projections24 for a locking screw 25. In this way, a ball-and-socket joint K isformed between a stationary holding means 26, which can also be theholding member 2 of FIG. 1, and the shield surface A, saidball-and-socket joint K permitting the transverse position of the shieldsurface A to be adapted to the respective supply direction R (inalignment with the passage axis f) or R1 or R2 (extending both at anoblique angle to the passage axis f).

The shield surface A according to FIG. 4 may also be used independentlyfor thread-guiding tasks at locations at which a thread eye or threadopening (13, 22, 19), in which the incoming thread must not getentangled, is required in the thread path. By means of theball-and-socket joint K, the shield surface A can be adjusted in eachcase to a position in which it extends approximately at right angles tothe supply direction. Instead of a ball-and-socket joint it would justas well be possible to use a universal joint or a cardan joint. If theball-and-socket joint K is used as direction adjustment means M in thecase of a thread braking device B according to FIG. 6, it will not benecessary to reposition the basic member 1 about the passage axis fbecause the shield surface A can be adjusted to all sides.

In the case of the embodiment of the thread braking device B of FIG. 5,part of the direction adjustment means M is formed between the shieldsurface A and the holding member 2 of the basic member 1, whereasanother part of said direction adjustment means is formed in the area ofthe support means 4' of the basic member 1.

The shield surface A is defined by a circular or oval flat plate 11',which consists of plastic material or of sheet metal and which hascentrally arranged therein the thread eye 13 provided on the supplyside. The extension 12" arranged at the back of the shield surface A hastwo diametrically opposed studs 27 defining a transverse axle 27a, whichcrosses the passage axis f. The studs 27 are frictionally held in pivotbearings 28, preferably in fork-shaped pivot bearings. The pivotbearings 28 are attached to a fork-shaped holding member 29, which isintegrally connected with the holding member 2.

An opening of a base plate 30 has arranged therein the thread eye 6,which is provided on the outlet side. Said plate 30 is equipped with acircular collar 31, which is in engagement, e.g. in frictionalengagement, with an opening 34 of a base plate 32.

The fastening means 5 are provided in said base plate 32. A lockingscrew 33 secures the rotary position of the basic member 1 about thepassage axis f. A similar fastening screw may also be provided betweenthe studs 27 and the pivot bearings 28, or in the ball-and-socket jointK in FIG. 4. Depending on the respective supply direction R, the shieldsurface A is rotated about the transverse axle 27a and the basic member1 is rotated about the passage axis f, until the shield surface Aextends approximately at right angles to the supply direction of thethread.

A lamella brake, a thread brake having two opposing brake elements(commonly known as a crocodile brake), a brake operating with a memberaround which the thread is at least partially wound, a slack take-updevice producing a braking effect, a deflection brake or the like can beused instead of the disk brake 3.

I claim:
 1. A thread braking device for use on the supply side of athread feeder, such as a thread storage and feed device, comprising asupport frame, a thread brake having a fixed thread passage axis, ashield member having an enlarged shield surface positionable to extendgenerally perpendicularly relative to a supply direction of a threadincoming from a supply to the thread brake, the shield member positionedfor cooperation with the incoming thread upstream of the brake andhaving an incoming thread guide opening formed in and extending throughsaid shield surface, direction adjustment means for permitting theshield surface to be adjustably moved between at least first and secondpositions which correspond to first and second incoming thread supplydirections, and positive locking means for maintaining the shieldsurface at a desired position which is generally perpendicular to theincoming thread direction, said direction adjustment means including anoutgoing thread guide opening disposed close to but located downstreamof said incoming thread guide opening for permitting the incoming threadwhen discharged from the direction adjustment means to be supplied tothe thread brake along the fixed thread passage axis, said outgoingthread guide opening being positioned for intersecting said fixed threadpassage axis when said shield member is in said first and secondpositions.
 2. The brake device according to claim 1, wherein saiddirection adjustment means further includes a first part which is fixedto and projects downstream of said shield member and defines a threadguide passage which at least in part is aligned with and projectsdownstream from said incoming thread guide opening, said outgoing threadguide opening being defined by said passage adjacent a downstream endthereof, said direction adjustment means also including a second partassociated with said frame and rotatably supporting said first part sothat the latter can be rotatably displaced between said first and secondpositions which respectively correspond to first and second incomingthread directions which are inclined with respect to one another so thatthe shield surface extends generally perpendicularly with respect to theincoming thread direction of the respective position.
 3. The brakedevice according to claim 2 wherein said first part and said second partform a rotary connection having an axis of rotation that intersects saidfixed thread passage axis at a first oblique angle, said shield surfacebeing arranged at a second oblique angle relative to a plane extendingat right angles to said axis of rotation.
 4. The thread brake device asclaimed in claim 3, wherein said first oblique angle and said secondoblique angle are each approximately equal to 22.5°.
 5. The brake deviceaccording to claim 4, wherein said first and second oblique angles sumto approximately 45° when said shield member is in said first position,and said first and second oblique angles sum to approximately 0° whensaid shield member is in said second position.
 6. The braking deviceaccording to claim 2, wherein said direction adjustment means furtherincludes means for rotatably positioning said frame with respect to saidfixed thread passage axis, and fastening means for fixedly securing saidframe to said thread storage and feeding device to maintain a desiredframe position relative to said thread storage and feed device.
 7. Thebrake device according to claim 2, wherein the first part includes acentral base portion projecting downstream from said shielding surfacealong a longitudinal central axis and having an end wall projecting at afirst oblique angle with respect to said shielding surface, and anexternally threaded projection extending transversely from said end wallalong an axis of rotation.
 8. The brake device according to claim 7,wherein said frame includes a holding member, a tongue member extendingat a second oblique angle with respect to said holding member, andsupport means for securing said frame to a supply side of said threadstorage and feed device.
 9. The brake device according to claim 8,wherein said second part includes an aperture in said tongue member,said projection having a free end thereof extending through saidaperture, and said tongue member rotatably supporting said end wall ofsaid central base portion on a first surface of said tongue member. 10.The brake device according to claim 9, wherein said positive lockingmeans includes a counternut which threadably engages said free end ofsaid projection, and which threadably abuts a second surface of saidtongue member to fixedly secure said shield member at a selectedposition.
 11. The brake device according to claim 1, wherein saidincoming thread guide opening includes a first thread eye disposedtherein, and said outgoing thread guide opening includes a second threadeye disposed therein.
 12. The brake device according to claim 11,wherein said first and second thread guide openings are formed from aceramic material.